Gases, such as oxygen, nitrogen and argon, are delivered to a use point in a number of ways. When the use of such gases requires a relatively small quantity of gas at one time, such as in metal cutting, welding, blanketing or metal fabrication operations, the gas is typically delivered to the use point and stored there in a gas storage cylinder.
Most cylinders in use in the United States today are manufactured in accordance with U.S. Department of Transportation Specification 3AA which requires that gas cylinders be constructed of designated steels, including 4130X steel. Cylinders conforming to this Specification 3AA are considered safe and exhibit good fracture toughness at the allowed tensile strengths.
With increasing transportation costs, there has arisen a need for an improved gas storage cylinder. In particular there has arisen a need for a gas storage cylinder which has much better cylinder efficiency than that of Specification 3AA. However, any such increase in cylinder efficiency cannot be at the expense of cylinder fracture toughness at the usable tensile strengths.
Since tensile strength and fracture toughness are, to a large extent, characteristic of the material of which the cylinder is made, it would be highly desirable to have a material to construct a gas storage cylinder which has improved cylinder efficiency while also having improved tensile strength and fracture toughness.
It is therefore an object of this invention to provide a steel and a gas storage cylinder manufactured thereof which has increased cylinder efficiency over that of conventional gas storage cylinders.
It is another object of this invention to provide a steel and a gas storage cylinder manufactured thereof which has increased ultimate tensile strength over that of conventional gas storage cylinders.
It is yet another object of this invention to provide a steel and a gas storage cylinder manufactured thereof which has increased temper resistance over that of conventional gas storage cylinders.
It is a further object of this invention to provide a steel and a gas cylinder manufactured thereof which has increased high temperature strength over that of conventional gas storage cylinders.
It is a still further object of this invention to provide a steel and a gas storage cylinder manufactured thereof which has increased fracture toughness over that of conventional gas storage cylinders.